This invention relates to the processing of optical fibers and, more particularly, to apparatus for baring an end of a sheathed optical fiber.
Individual optical fibers are typically provided with a protective outer sheath. Such a sheath may have one or more layers. Thus, a typical optical fiber has a diameter of approximately five mils and is covered with a polymer layer (the primary coating) with an overall diameter of approximately ten mils. The primary coating may optionally be covered by a polymer secondary coating with an overall diameter in the range from about thirty-five mils to about one hundred mils. For the sheathed fiber to be secured to a connector or to be spliced to another fiber, a length of the fiber adjacent an end must be bared by removing the coating(s) over that length.
When stripping the coatings from an optical fiber protected by two layers of polymer, this is done as a two-step procedure. In the first step, a length of the secondary coating is removed to expose the primary coating. This is done by cutting through the secondary coating to separate the unwanted length of the secondary coating from the rest of the secondary coating and then pulling the unwanted length of the secondary coating off the primary coating. Then, a shorter length of the exposed primary coating is removed in a similar manner. Until now, such baring of an end of an optical fiber has been done manually, using commercially available handheld stripping tools which apply heat for softening the coating to be removed. This manual operation introduces operator variability, which reduces the yield. This variability includes the length of time the heat is applied and the pull force applied to the removed length of coating. Further, the resulting bare fiber typically has traces of the removed primary coating on its surface, which requires a cleaning operation. In addition, the removed lengths of coating have to be removed from the stripping tool. It would therefore be desirable to provide an optical fiber stripping apparatus which eliminates operator variability, cleans the fiber, removes unwanted debris and is adaptable to be automated.